What a quarter! Dow and S&P at record highs

Finally. Stocks wrapped up a stellar first quarter Thursday with the S&P 500 finishing at a new high, after flirting with the milestone for weeks.

The benchmark index gained 6 points, or 0.4%, to end at a record close of 1569.19, inching above its previous record of 1565.15 from October 2007.

Despite the new milestone, trading was relatively calm and light as investors monitored the ongoing crisis in Cyprus and mulled over new economic data in the United States. The Dow Jones industrial average and the Nasdaq rose just a little over 0.3%. The markets will be closed tomorrow in the United States and most of Europe for Good Friday.

But the first quarter of 2013 has been far from quiet. The Dow, which has been trading at record highs since early March, rallied more than 11% and booked its best first quarter since 1998. The S&P 500 soared 10% and the Nasdaq was up 8%.

The biggest gains were logged in January, but March has been a solid month for stocks as well, with all three indexes rising more than 3%. Stocks continued to rally in the holiday-shortened week despite Cyprus concerns. The Dow rose 0.5% for the week, while the S&P 500 added 0.8% and Nasdaq rose 0.7%.

Despite the big run-up this year, experts argue that valuations remain attractive for U.S. stocks. The S&P 500 is trading at just 16 times 2012 earnings. At its all-time high in October 2007, the S&P 500's valuation was just above 17 times profits for the past 12 months.

And looking at earnings projections, stocks still appear reasonably valued. The S&P 500 is trading at just 14 times 2013 estimates.

Winners and losers: The best-performing stock in the S&P 500 during the quarter was Netflix(NFLX). Shares have more than doubled in the last few months as investors have become optimistic about the company's growth prospects, despite a series of missteps over the last couple of years. Best Buy(BBY) and Hewlett-Packard(HPQ), struggling companies that are in the middle of turnaround efforts, were the next strongest performers, with shares up 87% and 68% respectively.

Some of the weaker links were JC Penney(JCP), which is having more trouble than success with its makeover plan, as well as coal company Peabody Energy(BTU) and mining firm Cliffs Natural Resources(CLF).

Cyprus banks back to business:Banks in Cyprus reopened Thursday morning after being closed since March 16. The island nation plans to limit the amount of money that depositors can withdraw in an attempt to prevent bank runs.

Cyprus agreed early Monday to raise billions of euros from big depositors at the Bank of Cyprus and Popular Bank of Cyprus, and to shrink its banking sector in return for a €10 billion European Union bailout.

U.S. economy humming along: Back in the United States, the government released its weekly data on initial jobless claims and its final reading on fourth-quarter GDP.

Jobless claims totaled 357,000 in the week ended March 23, an increase of 16,000 from the prior week and much worse than expected. The forecast called for a total of335,000, according to a consensus of economists complied by Briefing.com.

The final government report for fourth-quarter GDP showed an annual increase of 0.4%, slightly higher than the expected increase of 0.3%. The prior reading showed the economy grew at a 0.1% pace.

What's moving:Blackberry(BBRY) slipped after the smartphone maker reported a surprise profit, but sales that fell short of expectations.

Pinnacle Foods(PF), owner of brands including Duncan Hines and Birds Eye, rose 11% in its stock market debut. Pinnacle raised $580 million in its initial public offering after pricing shares at the high end of its range. The company is backed by private equity firm Blackstone(BX).

Shares of Deckers Outdoor(DECK), which owns the Ugg boots brand, jumped after an analyst at Jefferies upgraded the stock and gave it a price target of $100 a share, nearly double its current price.

The price on the 10-year Treasury rose slightly, and the yield held steady at 1.85%.

What's buzzing: Wall Street strategists are betting the rally will continue. Wells Fargo Advisors increased its year-end 2013 target range for the S&P 500 to 1575-1625 from an earlier forecast of 1525-1575.

"Investors now appear to be more focused upon the potential for continuing global economic growth, said Scott Wren, senior equity strategist at Wells Fargo Advisors. "We anticipate investor confidence will continue to lift, slowly catching up with consumer confidence."